Have you seen a sinkhole in Hilton Head or Bluffton maybe? Here’s how and why they form
Potholes are common on roads, but larger and more dangerous holes are possible in Beaufort County.
When a large hole opens on the road, it could be a sinkhole. Two large holes have caused road delays in Beaufort County in the past few months.
But not all holes on the road are naturally occurring sinkholes. Here’s all you need to know about sinkholes and why they happen:
Why do they happen?
Sinkholes are caused by the erosion of ground below the surface, usually by water moving underground. When the ground erodes, it creates a cave that can not support the surface. The surface then collapses into the void, creating the sinkhole.
Potholes are different from sinkholes, in that they form due to failures in roadway materials. Water can play a role, but the large voids that create sinkholes don’t occur with potholes.
Sinkholes can form anywhere, not just under roadways. Regions with what geologists call karst terrain are most susceptible to sinkholes. Karst terrain is ground with rock that is easily dissolved by groundwater. All of Beaufort County sits atop karst terrain, according to the United States Geological Survey.
Beaufort County also sits on what the South Carolina Department of Natural Resources Geological Survey calls high potential for liquefaction ground. Liquefaction is when an earthquake turns the ground into a liquid-like state. SCDNR identified the area around the Town of Beaufort as having the potential for sinkholes, due to karstic features in its ground.
But not all holes are natural sinkholes. A large hole opened up on Bluffton Road, caused by a break in a water pipe. Pipes are usually installed away from roads, Beaufort-Jasper Water & Sewer Authority Chief Communications Officer Jeff La Rue said.
Beaufort County’s rapid growth led to roads being widened over water pipe infrastructure, he said. The vast majority of sinkholes are not related to water pipes however, he said. Sinkholes can be caused by man-made underground structures as well.
What to do if you see a sinkhole
If a hole opens on your property, first determine if it is natural or caused by a water-pipe leak. Contact BJWSA’s emergency dispatch at 843-987-9200 if water is spouting or pouring from the hole. If the hole is a natural sinkhole, contact the SCDNR Geological Survey at (803) 896-1214.
If you encounter a sinkhole on the road in one of Beaufort County’s towns, report it to town authorities. If you encounter one on a state road, such as U.S. and state highways, report it to the South Carolina Department of Transportation. Do not drive over or near sinkholes.